The device, which researchers say is expected to cost no more than £1, is environmentally friendly as the paper sensor is made from biodegradable components.

It weighs less than 1g, so is easy to transport.

Dr Mirella Di Lorenzo, senior lecturer at the University of Bath’s Department of Chemical Engineering, said: “This work could lead to a revolutionary way of testing water at the point of use, which is not only green, easy to operate and rapid, but also affordable to all.

“This type of research will have a significant positive impact, especially benefiting those areas where access to even basic analytic tools is prohibitive.

“This device is a small step in helping the world realise the United Nations’ call to ensure access to safe drinking water and sanitation as a human right.”

Access to safe drinking water is one of the UN’s Sustainable Development Goals.

The researchers are now investigating how to link up the sensor with an electric device such as a mobile phone, via a wireless transmitter.

This could create a user-friendly way of identifying if a water supply is safe to use.

Dr Janet Scott, reader in the University of Bath’s Department of Chemistry, said: “This is a great example of how scientists and engineers working closely together can develop useful technologies with the potential to impact positively on the lives of citizens globally – we were able to design the materials that facilitated the production of these devices and the engineering partners designed the devices.”